Merge

Author: AlanBateman

test/jdk/java/lang/Thread/virtual/stress/SkynetWithMonitors.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @summary Stress test virtual threads with a variation of the Skynet 1M benchmark that uses
+ *   a channel implementation based on object monitors
+ * @requires vm.continuations
+ * @run main/othervm/timeout=300 -Xmx1500m SkynetWithMonitors 2
+ */
+
+public class SkynetWithMonitors {
+
+    public static void main(String[] args) {
+        int iterations = (args.length > 0) ? Integer.parseInt(args[0]) : 1;
+        for (int i = 0; i < iterations; i++) {
+            skynet(1_000_000, 499999500000L);
+        }
+    }
+
+    static void skynet(int num, long expected) {
+        long start = System.currentTimeMillis();
+        var chan = new Channel<Long>();
+
+        Thread.startVirtualThread(() -> skynet(chan, 0, num, 10));
+
+        long sum = chan.receive();
+        long end = System.currentTimeMillis();
+        System.out.format("Result: %d in %s ms%n", sum, (end-start));
+        if (sum != expected)
+            throw new AssertionError("unexpected result!");
+    }
+
+    static void skynet(Channel<Long> result, int num, int size, int div) {
+        if (size == 1) {
+            result.send((long)num);
+        } else {
+            var chan = new Channel<Long>();
+            for (int i = 0; i < div; i++) {
+                int subNum = num + i * (size / div);
+                Thread.startVirtualThread(() -> skynet(chan, subNum, size / div, div));
+            }
+            long sum = 0;
+            for (int i = 0; i < div; i++) {
+                sum += chan.receive();
+            }
+            result.send(sum);
+        }
+    }
+
+    static class Channel<T> {
+        private final Object lock = new Object();
+        private T element;
+
+        Channel() {
+        }
+
+        void send(T e) {
+            boolean interrupted = false;
+            synchronized (lock) {
+                while (element != null) {
+                    try {
+                        lock.wait();
+                    } catch (InterruptedException x) {
+                        interrupted = true;
+                    }
+                }
+                element = e;
+                lock.notifyAll();
+            }
+            if (interrupted)
+                Thread.currentThread().interrupt();
+        }
+
+        T receive() {
+            T e;
+            boolean interrupted = false;
+            synchronized (lock) {
+                while ((e = element) == null) {
+                    try {
+                        lock.wait();
+                    } catch (InterruptedException x) {
+                        interrupted = true;
+                    }
+                }
+                element = null;
+                lock.notifyAll();
+            }
+            if (interrupted)
+                Thread.currentThread().interrupt();
+            return e;
+        }
+    }
+}